Nozzle plate for droplet ejection head

Abstract

A nozzle plate for a droplet ejection head includes one or more strips (each strip including one or more sub-strips, each including one or more droplet ejection nozzles) and one or more frames having one or more openings, each of the one or more sub-strips fitting within a corresponding opening in the one or more frames, and the one or more strips and the one or more frames together forming a medium-facing surface of the nozzle plate. Also provided are a droplet ejection head including one or more nozzle plates, a droplet ejection device including one or more droplet ejection heads, and a method for manufacturing a nozzle plate.

Description

[Technical Field]

[0001] The present disclosure relates to a nozzle plate for a droplet ejection head. The nozzle plate is particularly suitable for droplet ejection heads, such as drop-on-demand inkjet printheads, and more generally, for droplet ejection devices, specifically, for droplet ejection devices having one or more nozzle plates. The nozzle plate may include one or more nozzle arrays, at least one of which may be fluidly connected to a respective fluid chamber with an actuator. The actuator is actuated in response to an electrical signal to eject droplets from the nozzle in a jet direction. In many applications, a robust nozzle plate is desirable, able to withstand the rigors of the operating environment and prevent damage during cleaning. Such robust nozzle plates may be constructed, for example, from silicon nozzle plates. However, such robust nozzle plates can be expensive. The present disclosure relates to a nozzle plate with higher robustness at a lower cost. The present disclosure also describes a method for manufacturing such a nozzle plate. [Background technology]

[0002] Droplet ejection heads are now widely used in applications ranging from traditional inkjet printing to 3D printing and other rapid prototyping technologies. As a result, inks and other liquids may have novel chemical properties that allow them to adhere to new substrates and enhance the functionality of the deposited materials. Droplet ejection heads have been developed for industrial applications, including direct printing on substrates such as ceramic tiles and textiles, and for forming elements such as color filters in LCD and OLED displays for flat-screen televisions. These industrial printing techniques using droplet ejection heads enable short-run production runs, product customization, and even the printing of custom designs. It is clear, therefore, that droplet ejection heads continue to evolve and specialize to suit new and increasingly challenging applications. However, despite much development in the droplet ejection head field, there remains room for improvement.

[0003] In recent years, silicon nozzle plates have gained popularity due to their superior properties compared to nozzle plates made from softer materials such as polyimide, such as their ability to be precisely molded and their robustness. For example, in some industrial applications, nozzle plates can accidentally deposit liquid, such as curable ink, on the media-facing surface during operation, resulting in the ink curing. While such cured ink can sometimes only be removed by strong friction, nozzle plates made from silicon (or similarly strong materials) can withstand harsh cleaning procedures without sustaining scratches or other damage. While these nozzle plates solve the robustness issue, they can also be costly. This is because they can be quite large, with only six or seven nozzle plates fitting on a six-inch silicon wafer (the imperial unit of measurement commonly used for these wafers).

[0004] The present invention has been made in view of the above problems. Summary of the Invention

[0005] Aspects of the invention are set out in the accompanying independent claims, and details of particular embodiments of the invention are set out in the accompanying dependent claims.

[0006] According to a first aspect of the present invention, there is provided a nozzle plate for a droplet ejection head, the nozzle plate comprising one or more strips each including one or more sub-strips, the one or more sub-strips each including one or more droplet ejection nozzles, and one or more frames each including one or more openings, each of the one or more sub-strips fitting within a corresponding opening in the one or more frames, the one or more strips and the one or more frames together forming a medium-facing surface of the nozzle plate.

[0007] According to a second aspect of the present invention, there is provided a droplet ejection head comprising one or more nozzle plates according to the first aspect and one or more fluid chambers fluidly connected to one or more of the droplet ejection nozzles, wherein the fluid chambers comprise actuators operable to eject droplets of fluid from one of the one or more droplet ejection nozzles in response to an ejection command.

[0008] According to a third aspect of the present invention, there is provided a droplet ejection device comprising one or more droplet ejection heads according to the second aspect.

[0009] According to a fourth aspect of the present invention, there is provided a method for manufacturing a nozzle plate for a droplet ejection head, the method comprising the steps of: - forming a release layer on the top surface of the substrate; - forming a seed layer on the release layer; - placing one or more sub-strips on the seed layer and holding them in place using a temporary adhesive; - forming one or more frames around one or more sub-strips, such that each of the one or more sub-strips fits within a corresponding opening in the one or more frames; - Releasing the nozzle plate from the substrate;

[0010] According to a fifth aspect of the present invention, there is provided an alternative method for manufacturing a nozzle plate for a droplet ejection head, the method comprising the following steps: - Form a frame. - Forming one or more openings in the frame, each of which is provided with a support shelf. - Placing adhesive on a support shelf within the opening and / or on a portion of the opening border edge. - One or more sub-strips are placed in each opening so that a portion of the sub-strip is supported by the support shelf. - Allow the adhesive to cure to attach the sub-strip to the frame. [Brief explanation of the drawings]

[0011] [Figure 1A]1 shows a schematic diagram of a nozzle plate according to one embodiment of the present invention, comprising a frame and two strips, each containing sub-strips. [Figure 1B]

[0023] Figure 2A is an end view showing the thickness of the nozzle plate of the embodiment of Figure 1A. Figure 2A shows a schematic diagram of a nozzle plate according to another embodiment, similar to Figure 1A, but comprising a single strip divided into two sub-strips. [Figure 2A] 1B shows a schematic diagram of a nozzle plate according to another embodiment similar to FIG. 1A but comprising a single strip divided into two sub-strips. [Figure 2B] 2B is an end view of the embodiment of FIG. 2A showing the thickness of the nozzle plate and the fluid chamber below the nozzle plate. [Figure 2C] 2B is a side view of the embodiment of FIG. 2A showing the nozzle plate and the fluid chamber below the nozzle plate. [Figure 3] 1B is a schematic view similar to FIG. 1A of a nozzle plate according to another embodiment further including an outer frame. [Figure 4] 4 shows a schematic diagram of a nozzle plate according to another embodiment, similar to FIG. 3, in which there are multiple bridges connecting two frames. [Figure 5] 2B shows a schematic diagram of a nozzle plate according to another embodiment, similar to FIG. 2A, in which the strip comprises multiple sub-strips with stepped portions. [Figure 6] 2B shows a schematic diagram of a nozzle plate according to another embodiment, similar to FIG. 2A, in which the sub-strips are offset from one another and are non-uniform. [Figure 7A] 1 is a schematic diagram illustrating a portion of a nozzle plate according to another embodiment including a frame with a support ledge. [Figure 7B] 7B shows an end view of a portion of the nozzle plate of FIG. 7A. [Figure 7C] 7A and 7B show a schematic diagram of an embodiment of a nozzle plate with the frame of FIGS. 7A and 7B, with two strips inserted into the frame and supported by a support shelf. [Figure 8A] 7D is a schematic diagram of another embodiment of a nozzle plate, similar to FIG. 7C. [Figure 8B] 8B shows an end view of the nozzle plate of FIG. 8A. [Figure 9A] 1 illustrates a first step in the manufacturing process of a nozzle plate according to one embodiment. [Figure 9B] 4 illustrates a second step in the manufacturing process of a nozzle plate according to one embodiment. [Figure 9C] 1 illustrates a third step in the nozzle plate manufacturing process according to one embodiment. [Figure 9D] 4 illustrates a fourth step in the nozzle plate manufacturing process according to one embodiment. [Figure 9E] 1 illustrates a fifth step in the process of manufacturing a nozzle plate according to one embodiment. [Figure 9F] 1 illustrates a sixth step in the manufacturing process for a nozzle plate according to one embodiment. Note that the drawings are not to scale and certain features may be shown in exaggerated size for greater clarity. Detailed Description of the Drawings

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments and various implementations thereof will now be described with reference to the drawings, wherein like reference numerals are used where appropriate to refer to like elements throughout the following description.

[0013] FIG. 1A is a schematic diagram of a nozzle plate 170 for a droplet ejection head according to an embodiment, including a frame 60 and two strips 92a and 92b. Each strip 92a and 92b can include one or more sub-strips 93. In the embodiment of FIG. 1A, each strip 92a and 92b includes sub-strips 93a and 93b, respectively. FIG. 1B is an end view of the embodiment of FIG. 1A, showing that the nozzle plate 170 has a thickness t in the ejection direction 15, which is the direction in which droplets are ejected during use (in this case, the ejection direction 15 is the negative Z direction). The nozzle plate 170 has a medium-facing surface 118. The medium-facing surface 118 is the outer surface of the nozzle plate 170 when the nozzle plate 170 is mounted in a droplet ejection head, and faces the medium from which droplets are ejected (thus, during use, the ejection direction 15 is perpendicular to the medium-facing surface 118). It can be seen that the nozzle plate 170 is arranged with two strips 92a, 92b, each of which includes a substrip 93a, 93b, and each of the substrips 93a, 93b includes one or more droplet ejection nozzles 131. The frame 60 has two openings 61a, 61b, each of which is surrounded by the opening 61a, 61b, and each of the openings 61a, 61b is arranged adjacent to the outer peripheral edges 94a, 94b of each of the substrips 93a, 93b. The strips 92a, 92b and the frame 60 form the medium-facing surface 118 of the nozzle plate 170. It can also be seen that the boundary edges 64a, 64b of the openings 61a, 61b correspond to the shapes of the outer peripheral edges 94a, 94b, respectively.

[0014] Each strip 92a, 92b includes a plurality of nozzles 131 arranged in an array 130a, 130b, respectively, and extending in the array direction 10. The strips 92a, 92b are arranged adjacent to one another but are separated in the spacing direction 5 by a separation distance Sd. In the embodiment of FIG. 1A, there are two strips 92a, 92b, but more generally, the nozzle plate 170 may include one or more strips 92, with the droplet ejection nozzles 131 arranged in one or more nozzle arrays 130a, 130b extending in the array direction 10. Furthermore, when more than one such strip 92 is present, adjacent strips 92 may be offset from one another in the spacing direction 5 by a separation distance Sd, where Sd is measured between adjacent, aligned outer edges of each strip 92, as shown in FIG. 1A. Furthermore, although FIG. 1A shows that the strips 92a, 92b are aligned with each other at both ends of the array direction 10, this is not necessary, and in other arrangements the strips 92a, 92b may be offset from each other in the array direction 10, in which case the separation distance Sd is measured by protruding from the end of the strip 92 in the array direction 10.

[0015] As can be seen in FIG. 1A , both substrips 93a and 93b include indentation anchors 95a_i1 and 95b_i2 at one end of the strips 92a and 92b in the alignment direction 10. Two different types of indentation anchors 95 are shown: a partial circle 95a_i1 and a T-shape 95b_i2. Here, indentation refers to the anchors 95 removing material from the substrips 93a and 93b and filling the indents thus formed with material attached to or contained in the frame 60. It is generally understood that the anchors 95 do not necessarily have to be indentation anchors 95_i. In some configurations, the nozzle plate 170 may include anchors 95 that are protrusions 95_p and / or indents 95_i. Furthermore, it should be understood that the two shapes of the indentation anchors 95_i shown in FIG. 1A are by no means limiting, and any suitable shape may be used. Furthermore, the anchors may have the same or different shapes on different substrips 93. 1A, it should be understood that although the indentation anchors 95 are shown at one end of the substrips 93a, 93b, this is not required and the anchors may be formed at any suitable location on the outer peripheral edge 94 of each of the substrips 93. It should also be understood that the anchors need not be aligned between the strips 92, but may be located in different locations on different substrips 93.

[0016] Anchors 95 are for securing each sub-strip 93a, 93b within the frame 60. Anchors 95a_i1, 95b_i2 are seen to be located on the outer periphery 94 of each sub-strip 93a, 93b. While one anchor is shown per sub-strip 93a, 93b in FIG. 1A, this is not intended to be limiting, as one or more sub-strips 93a, 93b may include one or more anchors 95 for securing the one or more sub-strips 93a, 93b within the frame 60.

[0017] It is generally understood that the strips 92a, 92b and sub-strips 93a, 93b can be constructed of a moderately wear-resistant but expensive material, such as silicone. It is also generally understood that the frame(s) 60 can be constructed of a suitable material that is cheaper and / or less wear-resistant than the material of the sub-strips 93a, 93b, and thus the strips 92a, 92b. By constructing the nozzle plate 170 in this manner, the overall cost of the nozzle plate 170 can be reduced while taking advantage of the beneficial properties of wear-resistant materials. The beneficial properties of wear-resistant materials mean, for example, improved resistance to cleaning operations such as wiping, which can prevent or reduce or delay nozzle damage during use, thereby extending the life of the nozzle plate while reducing overall costs.

[0018] Turning now to FIG. 2A, a schematic diagram of a nozzle plate 270 according to another embodiment is shown, similar to FIG. 1A, except that one strip 92 is divided into two sub-strips 93i, 93ii (compare FIG. 1A, which includes two strips 92a, 92b, each including a single sub-strip 93a, 93b). FIG. 2B shows an end view of the embodiment of FIG. 2A, illustrating the nozzle plate thickness t and multiple fluid chambers 121 below the nozzle plate 270. The fluid chambers 121 are arranged in an array 120 extending in the array direction 10 corresponding to the array of nozzles 130, with at least one nozzle 131 per fluid chamber 121 fluidly connected to the fluid chamber 121. Each fluid chamber 121 is actuatable (or includes an actuator) to eject one or more fluid droplets through at least one nozzle 131 in response to a firing command. FIG. 2C shows a side view of the embodiment of FIG. 2A, illustrating the nozzle plate 270 and the fluid chambers 121 below the nozzle plate 270.

[0019] In FIG. 2A , it can be seen that strip 92 comprises an array 130 of nozzles 131, which extends in the array direction 10 and is arranged in substrips 93i, 93ii. Furthermore, it can be seen that adjacent nozzles 131 within array 130 are staggered perpendicular to array direction 10 (i.e., in the spacing direction 5, or y-direction in this example). This staggered arrangement of nozzles 131 allows for the use of different jetting strategies, e.g., multi-phase jetting, such as three-phase jetting. Adjacent nozzles 131 can be offset from one another to compensate for phased jetting, for example, while printing the same print line on the print medium. It will be appreciated that this staggered arrangement of nozzles 131 is by no means required and may depend on the method of operation of the droplet ejection head; in other arrangements, nozzles 131 within a particular nozzle array 130 may all be at the same y-position, as shown in FIG. 1A .

[0020] In the embodiment of FIG. 2A, the substrips 93i and 93ii have the same shape, and each of the substrips 93i and 93ii includes staggered edge portions 97i_1, 97i_2, 97ii_1, and 97ii_2 disposed on opposite edges of the respective substrips 93i and 93ii. In the embodiment of FIG. 2A, the staggered edge portions 97i_1, 97i_2, 97ii_1, and 97ii_2 are disposed on both ends of each substrip 93i and 93ii in the array direction 10. As can be seen from FIG. 2A, the staggered edge portion 97i_2 of the first substrip 93i is adjacent to the corresponding staggered edge portion 97ii_1 of the second substrip 93ii, and is disposed opposite each other in a mosaic pattern. This is believed to facilitate the alignment and positioning of the substrips 93i and 93ii relative to each other. Furthermore, in this embodiment, it can be seen that staggered edges 97i_1, 97ii_2 are arranged on the outer peripheral edges 94i, 94ii of the substrips 93i, 93ii located at both ends of the strip 92 in the arrangement direction 10. It can be seen that matching staggered edges 64i_1, 64ii_2 are arranged on the outer peripheral edges 64i, 64ii of the openings 61i, 61ii of the frame 60, adjacent to the staggered edges 97i_1, 97ii_2 of the substrips 93i, 93ii. This arrangement facilitates alignment and positioning of the substrips 93i, 93ii, and therefore the strip 92, relative to the frame 60, and further facilitates alignment of the entire strip 92 relative to the frame 60.

[0021] Furthermore, it is generally understood that when each strip 92 includes two or more substrips 93, a gap g may exist between two substrips 93 having adjacent surfaces (see, for example, FIG. 2A , where offset edges 97i_2 are adjacent to and face offset edges 97ii_1, creating a gap g therebetween). The material in the gap g between two substrips 93i, 93ii may form part of the frame 60. The frame 60 includes openings 61i, 61ii for each substrip 93i, 93ii, which may be separated from each other by the gap g in the region where the two substrips 93 have adjacent surfaces. It is understood that the width of the gap g between adjacent substrips 93 is constrained by the nozzle spacing n, and that the nozzle spacing n within the array 130 is maintained even when the array 130 spans two or more substrips 93. For example, the nozzle pitch or spacing n may be 150 μm. To maintain the nozzle spacing ns while ensuring sufficient substrip material around the nozzles 131 adjacent the gap g between the substrips 93, the gap width can be reduced to around 20-40 μm.

[0022] FIG. 3 is a schematic diagram of a nozzle plate 370 according to another embodiment of the present invention. This embodiment is similar to the embodiment of FIG. 1A, with the main difference being that frames 60a, 60b are provided around each substrip 93a, 93b, and an outer frame 75 surrounds the two frames 60a, 60b. That is, in this embodiment, each frame 60a, 60b has one opening 61a, 61b, respectively. The outer frame 75 has two outer openings 76a, 76b, and each frame 60a, 60b is surrounded by the two outer openings 76a, 76b. It can be seen that the outer openings 76a, 76b preferably follow the shape of the outer peripheral edges 68a, 68b of the frames 60a, 60b. This means that the outer openings 76a, 76b closely follow the shape of the outer peripheral edges 68a, 68b. For example, if the frames 60a, 60b are formed in the spaces between the substrips 93a, 93b and the outer frame 75 by a method such as electroforming, growth of the frames 60a, 60b in the spaces between the substrips 93a, 93b and the outer frame 75 is limited by the edges of the substrips 93a, 93b and the edges of the outer openings 76a, 76b in the outer frame 75 adjacent to the growing frames 60a, 60b. Furthermore, using an alternative method, the frames 60a, 60b can be formed by filling the spaces between the substrips 93a, 93b and the outer frame 75 with a flowable material that conforms to the edges of the substrips 93a, 93b and the outer frame 75. The flowable material can then be cured or hardened using any suitable method to form the frames 60a, 60b. It is generally understood that methods of growing frames or using flowable materials that can then be hardened or hardened apply, where appropriate, to any of the embodiments described herein. More generally, any suitable method can be used to form one or more frames 60 that surround one or more sub-strips 93 .

[0023] FIG. 4 is a schematic diagram of a nozzle plate 470 according to another embodiment, similar to FIG. 3 . A plurality of bridges 81i-81iv are provided connecting two frames 60a, 60b, dividing the outer frame 75 into portions 75i-75iii in the region between the two frames 60a, 60b. While four bridges 81 are shown in FIG. 4 , other arrangements may include one or more bridges 81i-n (n is an integer). The bridges 81 are used to control the separation distance Sd between adjacent strips 92a, 92b. This improves alignment accuracy between the strips 92a, 92b, improving nozzle positioning accuracy and ultimately improving printing accuracy. It can be seen that the bridges 81 extend in the spacing direction 5 and are disposed between adjacent, spaced-apart strips 92, thereby controlling the distance between the strips 92. As can be seen in FIG. 4 , two of the bridges 81i, 81iv are perpendicular to the array direction 10 and parallel to the spacing direction 5. Meanwhile, two of the bridges 81ii and 81iii are inclined at an angle α with respect to the arrangement direction 10. This is not necessarily required, and other arrangements are possible, such as all bridges facing the same direction or all facing different directions. Furthermore, while multiple bridges 81 are shown in FIG. 4 , it should be understood that a single bridge 81 is sufficient. Furthermore, multiple bridges 81 may be arranged to form a pattern such as a zigzag, honeycomb, or basket weave. More generally, any suitable arrangement or layout of one or more bridges 81 may be used, and such bridges 81 may enable alignment of the substrips 93 and strips 92 with respect to one another. Generally, the nozzle plate 470 may include bridges 81 formed of the same material as the frame 60. Furthermore, the nozzle plate 470 may include one or more bridges 81, and at least one of the bridges 81 may be connected to one or more frames 60. Alternatively, the bridge 81 may be constructed of a different material from the frame 60. When the nozzle plate includes one or more outer frames 75 , the outer frames 75 may be positioned adjacent to and surrounding the periphery of one or more frames 60 .In some cases, they may be positioned adjacent to and surrounding one or more outer edges of the bridge 81.

[0024] FIG. 5 is similar to FIGS. 2A-2C but shows a schematic diagram of a nozzle plate 570 according to another embodiment. The strip 92 is composed of multiple substrips 93ai-93biii arranged in a tessellated pattern in both the array direction 10 and the spacing direction 5. In this embodiment, two arrays of nozzles 130a, 130b are housed within a single strip 92, separated by an array separation distance Ad in the spacing direction 5. Additionally, each substrip 93ai-93biii is shown to have steps at both ends of the array direction 10. For example, substrip 93bi has steps 97bi_1 and 97bi_2 on either side of the array direction 10, and steps 97bi_3 and 97bi_4 on either side of the spacing direction 5. It can be seen that all substrips 93ai-93bii have similar features, but for simplicity, not all are labeled and are numbered 93ai_1-93biii_4 in the same manner as substrip 93bi. In nozzle plate 570, each substrip 93 can be said to include four or more offset edge portions 97 arranged in two or more sets. A first set, e.g., 97_1, 97_2, can be on opposite edges of each substrip 93 in the array direction 10, and a second set, e.g., 97_3, 97_4, can be on opposite edges of each substrip 93 in the spacing direction 5.

[0025] The staggered edge portions 97 help align the substrips 93 relative to each other and to the strips 92 and frame 60, allowing nozzles 131 to be positioned to form nozzle arrays 130a, 130b. For example, if two substrips 93 are positioned adjacent to each other in the array direction 10, e.g., 93ai and 93aii, then the staggered edge 97ai_2 on the first substrip 93ai is adjacent to and opposite the corresponding staggered edge 97aii_1 on the second substrip 93aii, in the array direction 10, so that they are tessellated. Similarly, in the spacing direction 5, the staggered edge 97bi_4 on, e.g., substrip 93bi, is adjacent to and opposite the corresponding staggered edge 97ai_3 on substrip 93ai, so that they are tessellated.

[0026] The nozzle plate 570 of FIG. 5 includes a frame 60 having a plurality of openings 61ai-61biii, one for each of the substrips 93ai-93biii (not all openings are labeled in FIG. 5), with each substrip 93 being surrounded by an opening 61 in the frame 60. Furthermore, as shown in FIG. 3, the nozzle plate 570 includes an outer frame 75 surrounding the frame 60. The outer frame 75 includes an outer opening 76, which surrounds the frame 60. It can be seen that the openings 61ai-61biii are preferably shaped to match the shape of the outer peripheral edges 94ai-94biii of the substrips 93ai-93biii. It can also be seen that the outer opening 76 matches the shape of the outer peripheral edge 68 of the frame 60. It can further be seen that the shape of the outer opening 76 mirrors the shape of the outer peripheral edge 68, which in turn mirrors the shape of the outermost portion of the sub-strip 93, i.e., the outer peripheral edge 94, including the staggered edges 97 located adjacent to the outer opening 76.

[0027] FIG. 6 is a schematic diagram of a nozzle plate 670 according to another embodiment, similar to FIG. 5, except that the substrips 93 are non-uniform and offset to align the nozzle array 130 in the array direction 10. This arrangement may be used, for example, to maximize the available space on the die by using substrips 93 of different shapes, or to accommodate variations in shape between the substrips 93 to position the nozzles 131 as close as possible to their desired locations. While not shown, it will be understood that each substrip 93i-93vi in ​​FIG. 6 may include one or more anchors 95 and / or one or more offset edges 97, as described herein.

[0028] 7A, 7B, and 7C respectively show a schematic diagram illustrating a portion of an embodiment of a nozzle plate 770 including a frame 60 (FIG. 7A), an end view of the frame 60 (FIG. 7B), and a nozzle plate 770 with two strips 92a, 92b inserted into the frame 60 of FIGS. 7A and 7B (FIG. 7C). Looking first at FIG. 7A, it can be seen that the frame 60 includes two openings 61a, 61b, each with a border edge 64a, 64b. Furthermore, it can be seen that the frame 60 includes a stepped portion for each opening 61a, 61b, which defines a support shelf 67a, 67b configured to be positioned below the corresponding edge of each sub-strip 93a, 93b (see FIG. 7C). This arrangement may facilitate manufacturing and operation by providing support for the strips 92.

[0029] 7A-7C, the frame 60 can be constructed of glass or ceramic, or can be constructed of a polymer. An adhesive and / or sealant layer can be disposed between the support ledges 67a, 67b and the sub-strips 93a, 93b to ensure a fluid seal and / or to secure the sub-strips 93a, 93b to the support ledges 67a, 67b.

[0030] As can be seen in FIG. 7C , each strip 92 a, 92 b includes a plurality of nozzles 131 arranged in arrays 130 a, 130 b, respectively, extending in the array direction 10. In this embodiment, each strip 92 a, 92 b includes a single sub-strip 93 a, 93 b, respectively, but this is not limiting, and in other arrangements, there may be two or more sub-strips 93 per strip 92, as described above. The strips 92 a, 92 b are separated by a separation distance Sd in the spacing direction 5. In this embodiment, the spacing direction 5 is perpendicular to the array direction 10, but this is not limiting, and in other arrangements, two or more strips 92 are spaced apart from each other in the spacing direction 5, and the spacing direction 5 is at a non-parallel angle to the array direction 10.

[0031] 8A and 8B, similar to FIG. 7C, this embodiment includes an outer frame 75 having a stepped portion for each outer opening 76, which defines a support shelf 67a, 67b. The support shelves 67a, 67b are configured to cover the corresponding edges of the respective substrips 93a, 93b, and thus the corresponding strips 92a, 92b. A frame 60 is formed in the gap between the outer opening 76 and the substrips 93a, 93b, surrounding the substrips 93a, 93b. The frame 60 may be made of a resilient material, which is advantageous when the thermal expansion coefficients of the strips 92a, 92b differ from those of the frame 60 and the outer frame 75. Alternatively, a resilient filler may be added between the frame 60 and the strips 92a, 92b to form an interface region between the strips 92a, 92b and the frame 60. Similarly, when there is a difference in the thermal expansion coefficient between the frame 60 and the outer frame 75, an elastic filler may be disposed so as to form an interface region between the frame 60 and the outer frame 75.

[0032] Any of the nozzle plates 170-870 described herein can be assembled into a droplet ejection head. A droplet ejection head includes one or more nozzle plates 170-870 described herein and one or more fluid chambers, which are fluidly connected to one or more droplet ejection nozzles 131. The fluid chambers can include actuators operable to eject droplets of fluid from one of the one or more droplet ejection nozzles 131 in response to an ejection command. Each fluid chamber can include an actuator associated with the fluid chamber and operable to eject droplets through one or more nozzles 131 coupled to the respective fluid chamber. For example, one or more walls of the fluid chamber can be operable to eject droplets of fluid through one or more nozzles. In some cases, one or more side walls of each fluid chamber can include a material exhibiting piezoelectric properties and an appropriate drive electrode arrangement, or the fluid chamber can include a roof-mode actuator arrangement. However, it will be understood that other forms of actuators suitable for ejecting fluid from the respective fluid chambers through each nozzle 131 in response to an ejection command can also be used. The droplet ejection device may include one or more droplet ejection heads. The droplet ejection heads may include one or more nozzle plates as described herein.

[0033] 9A-9E summarize the major steps in the method for manufacturing a nozzle plate for a droplet ejection head described herein. These figures are based on nozzle plate 170 as shown in FIG. 1A, but it will be understood that the method can be appropriately adapted to manufacture other embodiments of the nozzle plate of the present invention. In this method, a frame 60 is used to surround strips 92 and / or substrips 93 to hold them securely in place with high precision. Frame 60 can be grown or formed around strips 92 and / or substrips 93, for example, by electroforming or other suitable processes known in the art. The major steps are as follows:

[0034] 1) As shown in Figure 9A, a substrate 99 can be used as a support for fabricating nozzle plates 170-870. The substrate 99 is reusable and can be made of glass or silicon. The substrate 99 can be large enough to accommodate multiple nozzle plates 170-870.

[0035] 2) As shown in FIG. 9B, a release layer 100 can be deposited on top of the substrate 99. This can be a resist layer, for example, that can be applied in an early stage and removed (e.g., using a dissolving or lift-off resist) at a later stage to release it from the substrate 99. The resist layer can be similar to photoresist or can be a substance that can be hardened to form a polymer film. Alternatively, a substrate 99 with appropriate properties, surface characteristics, or coatings / treatments to facilitate release of the nozzle plate 170-870 from the substrate 99 can be used. The substrate 99 can be glass, silicon, or any suitable material.

[0036] 3) FIG. 9C shows a seed layer 101 that can be used as a starting point for growing the frame 75. For example, the seed layer 101 can be a seed layer for an electrophoretic process, such as an electroplating process. The seed layer 101 can be deposited on a release layer 100. Regions 102 and 103, slightly smaller than the substrips 93 and strips 92, can be spaced apart from the seed layer 101 to avoid unwanted metal deposition and to prevent metal growth on the nozzle itself or contamination of the nozzle plate 170-870 adjacent to the nozzle 131. The regions 102 and 103 can be spaced apart from the seed layer 101, for example, by using an appropriate mask. The seed layer 101 can be deposited by sputtering, electroless plating, or the like. For example, a mask that can be removed by shadow masking or etching or plasma can be used to remove the metal mask in a later step.

[0037] 4) FIG. 9D shows two strips 92a, 92b, each including a single substrip 93a, 93b, which can be precisely positioned on the seed layer 101 and positioned to cover regions 102, 103. Each substrip 93a, 93b can include one or more nozzles 131, and each substrip 93a, 93b can include multiple nozzles 131. The substrips 93a, 93b can be temporarily held in place using, for example, a removable adhesive. FIG. 9D also shows anchors 95 (anchors 95a_i1 and 95b_i2 in FIG. 9D) positioned on the outer periphery 94 of each substrip 93a, 93b, although, as noted above, this is not required. It may further be understood that if one or more substrips 93 include two or more stepped portions 97, the step of disposing the substrips 93 may include disposing the two or more substrips 93 such that two of the stepped portions 97 are disposed adjacent to each other on opposite sides of the substrips 93. For example, as shown in FIG. 5 , 97bii_1 is disposed adjacent to 97bi_2 and 97bi_4 is disposed adjacent to 97ai_3. It may further be understood that the nozzles 131 may be formed in the strips 92a, 92b before disposing the strips 92a, 92b on the seed layer 101, or may be formed as a subsequent step after the strips 92a, 92b are in place.

[0038] It will be appreciated that where there are multiple substrips 93 arranged in one or more strips 92, the substrips 93 a, 93 b may be arranged such that the nozzles 131 in a given strip 92 are aligned to form one or more arrays 130 extending in the alignment direction 10. Additionally, the substrips 93 a, 93 b in adjacent strips 92 a, 92 b may be arranged such that the one or more arrays 130 a, 130 b, respectively, are parallel to one another. For example, the strips 92 may be aligned such that the droplet ejection nozzles 131 are arranged in one or more nozzle arrays 130 extending in the alignment direction 10.

[0039] 5) Referring to FIG. 9E, a frame 60 is grown around the substrips 93a, 93b, fixing the relative positions of the substrips 93a, 93b. If anchors 95 are present on one or more substrips 93a, 93b, it can be seen that forming the one or more frames 60 around the one or more substrips 93a, 93b can include forming a frame material within or around the one or more anchors 95. Methods for growing the frame 60 can include, for example, electrophoresis, electroplating, electroforming, electrodeposition, etc., depending on the thickness of the metal layer, so that the one or more frames 60 are comprised of an electroformed material. Alternatively, other suitable methods known in the art can be used. The one or more frames 60 can be comprised of a metal. For example, the one or more frames 60 can be comprised of nickel. Alternatively, a suitable polymer can be used that can be deposited using an electrophoresis process or other suitable methods known in the art.

[0040] 6) Finally, as shown in Figure 9F, the nozzle plate 170-870 is peeled from the substrate 99, for example, by dissolving or removing the release layer 100. If desired, the method may further include removing the seed layer 101 from the nozzle plate 170-870 after the step of peeling the nozzle plate 170-870 from the substrate 99 (see Figure 1A), although alternatively the seed layer 101 may be retained.

[0041] In summary, the method for manufacturing a nozzle plate 170-870 for a droplet ejection head includes the following steps. - forming a release layer 100 on the top surface of the substrate 99; - forming a seed layer 101 on the release layer 100; - Place one or more sub-strips 93 onto the seed layer 101, optionally using a temporary adhesive to hold them in place. - forming one or more frames 60 around one or more sub-strips 93, with each of the one or more sub-strips 93 fitting within a corresponding opening 61 in the one or more frames 60 (in other words, the one or more sub-strips 93 are surrounded by openings 61 in the frame 60, with each opening 61 positioned adjacent to one outer edge 94 of the sub-strip 93); - Release the nozzle plate 170-870 from the substrate 99.

[0042] It will be appreciated that the nozzles 131 may be formed in the substrips 93 prior to placement on the seed layer 101, or may be formed at an appropriate stage in the manufacture of the nozzle plate 170-870.

[0043] The manufacturing method may further include removing the temporary adhesive after releasing the nozzle plate 170-870 from the substrate 99.

[0044] The frame 60 can be formed, for example, using an electroplating process, where the step of forming the one or more frames 60 includes an electroplating process. The method can include electroplating nickel to form the one or more frames 60. Alternatively, the method can include electrophoresis, electroforming, or electrodeposition, depending on the material used for the frame 60.

[0045] In embodiments such as those shown in FIGS. 3 and 4, if an outer frame 75 is present, the method may further include forming the outer frame 75 before forming the one or more frames 60. For example, the outer frame 75 may be made of a polymer. It will be appreciated that the method for manufacturing the nozzle plate 170-870 may include forming the outer frame 75, for example, by spin coating and photolithography. This step may be performed before disposing the substrips 93 on the seed layer 101. An appropriate mask may be used to form the outer frame 75 in the desired location. Alternatively, the outer frame 75 may be formed after disposing the substrips 93 on the seed layer 101, in which case the substrips 93 may be appropriately masked during the formation of the outer frame 75.

[0046] Alternatively, the outer frame 75 may be a preformed part made of any suitable material and may be placed on the seed layer 101 in step 4), surrounding the location of the substrips 93, leaving a gap between the outer frame 75 and the location of the substrips 93. The substrips 93 may already be in place or may be placed after the outer frame 75 is in place. In this manufacturing method, one or more notches for forming the outer openings 76 may be preformed in the preformed part before attachment to the seed layer 101. Furthermore, in this manufacturing method, the outer frame 75 may be temporarily held in place using, for example, a removable adhesive. The outer frame 75 may be made of glass or ceramic. The outer frame 75 may be made of a polymer. Using an inexpensive material, such as glass, ceramic, or polymer, for the outer frame 75 may potentially reduce the overall cost of the nozzle plate 170-870.

[0047] Whether the outer frame 75 is fabricated on-site or comprises preformed parts positioned in place, step 5) may include forming one or more frames 60 around one or more substrips 93, wherein the one or more substrips 93 are surrounded by openings 61 in the frames 60, with each opening 61 positioned adjacent to one outer peripheral edge 94 of the substrips 93. Forming the frames 60 may further include forming the one or more frames 60 within the outer frame 75 such that the frames 60 fill spaces or gaps between the outer frame 75 and the substrips 93. For example, the manufacturing method for the nozzle plate 170-870 may include filling spaces or gaps between the outer frame 75 and the substrips 93. When two or more substrips 93 are spaced apart by a separation distance Sd and bridges 81 are formed between the substrips 93, the manufacturing method may include masking the bridges using an appropriate mask when forming the outer frame 75. The bridges 81 may be formed during the formation of one or more frames 60, for example, by electroplating or electroforming one or more frames 60 and, if present, bridges 81. If there are one or more bridges 81, the width of the bridges 81 may be appropriately adjusted so that the material filling the bridges 81 grows at the same rate as the frames 60 filling the spaces or gaps between the outer frame 75 and the sub-strips 93.

[0048] An alternative method for manufacturing a nozzle plate 170-870 for a droplet ejection head such as that shown in FIGS. 7A-7C and 8A-8B includes the following steps. - Forming frames 60, 75. - forming one or more openings 61a, 61b, 76a, 76b in the frame 60, 75, with a support shelf 67a, 67b in each opening 61a, 61b, 76a, 76b (see, for example, Figures 7A and 7B); - Placing adhesive on the support shelves 67a, 67b in the openings 61a, 61b, 76a, 76b and on portions of the opening border edges 64a, 64b. - placing one or more sub-strips 93 in each of the openings 61a, 61b, 76a, 76b such that a portion of the sub-strips 93 is supported by the support shelves 67a, 67b; - Allow the adhesive to cure to attach the sub-strips 93 to the frames 60,75.

[0049] Where the method includes placing substrips 93 in openings 61 a, 61 b, 76 a, 76 b to be supported by support shelves, adhesive or filler may be placed around the substrips 93 to fill gaps between the substrips 93 and openings 61 a, 61 b, 76 a, 76 b, as shown in FIG. 8B. In other words, the manufacturing method may include forming one or more frames 60 around one or more substrips 93, such that each of the one or more substrips 93 fits within a corresponding opening 61 of the one or more frames 60.

[0050] In some configurations, the manufacturing methods for the nozzle plates 170-870 described herein can include forming one or more openings 61a, 61b, 76a, 76b in the frame 60 or outer frame 75 using etching or sandblasting. In some manufacturing methods, one or more actuator components can be attached to one or more of the sub-strips 93 prior to placing the sub-strips 93 in the openings 61a, 61b, 76a, 76b. The nozzle plates 170-870 can include a configuration in which the boundary edge 64 of one or more openings 61 is formed to conform to the shape of the outer periphery 94 during manufacturing. General Considerations

[0051] Generally, a nozzle plate 170-870 described herein includes at least one strip 92 including one or more sub-strips 93, and at least one frame 60 having one or more openings 61. Each sub-strip 93 includes one or more droplet ejection nozzles 131, and each sub-strip 93 is configured to fit within the opening 61 of the corresponding frame 60. Together, the strips 92a, 92b and the frame 60 thereby form the medium-facing surface 118 of the nozzle plate 170-870.

[0052] In other words, each of the one or more substrips 93 is surrounded by one of one or more openings 61, and each of the openings 61 is disposed adjacent to the outer peripheral edge 94 of one of the substrips 93, so that the one or more strips 92 and the one or more frames 60 together form the medium-facing surface 118 of the nozzle plate 170-870. When the one or more frames 60 are surrounded by the outer frame 75, the medium-facing surface 118 of the nozzle plate 170-870 may further include the outer frame 75. It will be understood that the medium-facing surface 118 formed by the one or more strips 92, each including one or more substrips 93, the one or more frames 60, and the one or more outer frames 75 (if present) may be planar. It will be understood that when the nozzle plate 170-870 is composed of a single strip 92, there is no separation distance Sd, and the y direction indicates a direction perpendicular to the array direction 10 and the ejection direction 15.

[0053] It is understood that the nozzle plate 170-870 may include one or more nozzle arrays 130 in which the droplet-emitting nozzles 131 are arranged in a repeating pattern. The nozzle plate 170-870 may include droplet-emitting nozzles 131 that are staggered relative to one another.

[0054] The present invention provides one or more strips 92, each containing one or more substrips 93, and a means for attaching these strips to a frame 60. The frame 60 is formed from a low-cost material and constitutes the remaining surface of the nozzle plate 170-870. This arrangement reduces costs compared to a fully rigid nozzle plate, such as a silicon nozzle plate, while providing the desired robustness near the nozzles. This cost reduction is possible because many smaller strips can be fabricated from a standard 6-inch silicon wafer, eliminating the need to fabricate the entire nozzle plate 170-870 from an expensive material such as silicon. However, when positioning the individual strips (for droplet ejection heads with multiple nozzle rows or when using long nozzle rows), maintaining a durable high alignment tolerance relative to each other is important but difficult. The present invention proposes a means for aligning the strips relative to each other with a sufficiently high tolerance.

[0055] 1A-1B, 3, 4, 7C, 8A-8B, and 9F, when each strip 92 is composed of a single substrip 93, it is generally understood that such substrip 93 may have one or more offset edges 97 disposed at one or more locations on the outer periphery 94 of the strip 92 (i.e., one or more sides if the strip 92 is generally rectangular) to facilitate alignment and positioning of each strip 92 relative to an adjacent frame 60. This may be used in addition to or instead of the anchors 95 described above. For example, one or more staggered edges 97 may be located at one or both ends in the array direction 10, or one or more staggered edges 97 may be located at one or both ends parallel to the array direction 10. The nozzle plates 170-870 described herein include three or more substrips 93, with at least two substrips arranged adjacent to each other in the nozzle array direction 10 and at least two substrips 93 arranged adjacent to each other in the spacing direction 5. In such a nozzle plate 170-870, the offset edges 97 allow for a mosaic arrangement of three or more sub-strips 93.

[0056] The fluid chambers 121 described herein may include an actuator associated with each fluid chamber 121 and operable to eject droplets of fluid through one or more nozzles 131 associated with the respective fluid chamber 121. For example, one or more of the walls of the fluid chamber 121 may be operable to eject fluid droplets through one or more nozzles 131. For example, one or more side walls of each fluid chamber 121 may include a material exhibiting piezoelectric properties and a suitable drive electrode arrangement, or the fluid chamber 121 may include a roof-mode actuator arrangement. However, it will be appreciated that other forms of actuators suitable for ejecting fluid from the individual fluid chambers 121 through each nozzle 131 in response to a jetting command may be used.

Claims

1. A nozzle plate for a droplet ejection head, the nozzle plate comprising: one or more strips (92) comprising one or more sub-strips (93), said one or more sub-strips (93) comprising one or more droplet ejection nozzles (131); one or more frames (60) with one or more openings (61); each of the one or more sub-strips (93) fitted into a corresponding opening (61) of the one or more frames (60); the one or more strips (92a, 92b) and the one or more frames (60) together form a surface (118) of the nozzle plate facing the medium; Nozzle plate.

2. each of the one or more sub-strips (93) is surrounded by one of the one or more openings (61); 2. The nozzle plate of claim 1, wherein each of the openings (61) is located adjacent to an outer peripheral edge (94) of one of the sub-strips (93).

3. 3. The nozzle plate according to claim 1, wherein a boundary edge (64) of the one or more openings (61) conforms to the shape of the outer peripheral edge (94).

4. 4. A nozzle plate according to claim 1, wherein the strips (92) are aligned so that the droplet ejection nozzles (131) are arranged in one or more nozzle arrays (130) extending in an arrangement direction (10).

5. 5. A nozzle plate according to any one of claims 1 to 4, comprising two or more strips (92), adjacent strips (92) being offset in the spacing direction (5) by a separation distance (Sd).

6. The nozzle plate of any of claims 1 to 5, wherein the one or more frames (60) comprise an electrophoretic material.

7. The nozzle plate of any of claims 1 to 6, wherein the one or more frames (60) comprise metal.

8. The nozzle plate of claim 7, wherein the one or more frames (60) comprise nickel.

9. The nozzle plate of any of claims 1 to 5, wherein the one or more frames (60) comprise glass or ceramic.

10. The nozzle plate of any of claims 1 to 5, wherein the one or more frames (60) comprise a polymer.

11. 11. A nozzle plate as described in any one of claims 1 to 10, wherein the sub-strips (93) are provided with one or more anchors (95) for fixing the one or more sub-strips (93) within the one or more frames (60).

12. 12. The nozzle plate of claim 11, wherein the anchors (95) are located at the outer peripheral edges (94) of the sub-strips (93).

13. 13. The nozzle plate of claim 11 or claim 12, wherein the anchors (95) are protrusions and / or indentations.

14. 14. A nozzle plate as described in any one of claims 1 to 13, wherein the one or more frames (60) have stepped portions defining support shelves (67) configured to support corresponding ends of the sub-strips (93) from below.

15. 15. A nozzle plate according to any preceding claim, wherein the sub-strip (93) comprises one or more staggered edges (97) provided on the outer peripheral edge (94).

16. 16. A nozzle plate according to any preceding claim, wherein each of the sub-strips (93) comprises staggered ends (97) respectively located at opposite ends of the sub-strip (93).

17. A nozzle plate according to any preceding claim, wherein the sub-strips (93) are of the same shape.

18. 18. A nozzle plate as described in any one of claims 1 to 17, wherein each of the sub-strips (93) comprises four or more staggered ends (97) arranged in two sets (97a, 97b), each set being at an opposite end of the sub-strip (93).

19. 19. A nozzle plate as described in any one of claims 1 to 18, comprising two or more substrips (93) in which staggered ends (97i_2) on a first substrip (93i) of the substrips are adjacent to and arranged opposite a corresponding staggered end (97ii_1) on a second substrip (93ii) of the two or more substrips in a mutually overlapping manner.

20. 20. A nozzle plate as described in any one of claims 1 to 19, comprising three or more substrips (93), at least two of which are adjacent to each other and arranged so as to overlap each other in the nozzle arrangement direction (10), and at least two of which are adjacent to each other and arranged so as to overlap each other in the spacing direction (5), and the stepped portion (97) allows the three or more substrips (93) to be arranged so as to overlap each other.

21. 21. A nozzle plate according to any one of claims 1 to 20, comprising two or more strips (92) arranged at a distance from each other in a spacing direction (5), the spacing direction (5) being at an angle that is not parallel to the arrangement direction (10).

22. 22. The nozzle plate of claim 21, comprising bridges (81) extending in the spacing direction (5) and arranged between adjacent spaced apart strips (92) to control the distance between the strips (92).

23. 23. The nozzle plate of claim 22, wherein the frame (60) comprises the bridge (81) formed from the same material as the frame (60).

24. 24. A nozzle plate according to claim 22 or claim 23, wherein the bridge (81) is connected to the one or more frames (60).

25. 25. A nozzle plate as claimed in any one of claims 1 to 24, comprising one or more outer rims (75) arranged adjacent to and surrounding the outer periphery of the one or more frames (60), and, if dependent on any one of claims 22 to 24, adjacent to and surrounding the outer ends of one or more of the bridges (81).

26. 26. The nozzle plate of claim 25, wherein the one or more outer frames (75) comprise a polymer.

27. A droplet ejection head comprising one or more nozzle plates as described in any one of claims 1 to 26 and one or more fluid chambers (121) fluidly connected to one or more of the droplet ejection nozzles (131), wherein the fluid chambers (121) comprise an actuator that can be driven to eject droplets of fluid from one of the one or more droplet ejection nozzles (131) in response to an ejection command.

28. A droplet ejection device comprising one or more droplet ejection heads according to claim 27.

29. A method for manufacturing a nozzle plate for a droplet ejection head, comprising: forming a release layer (100) on the top surface of the substrate (99); forming a seed layer (101) on the release layer (100); providing one or more sub-strips (93) on the seed layer (101) and holding them in place with a temporary adhesive; forming one or more frames (60) around the one or more sub-strips (93), each of the one or more sub-strips (93) fitting into a corresponding opening (61) in the one or more frames (60); peeling the nozzle plate from the substrate (99).

30. 30. The method of claim 29, further comprising removing the seed layer (101) from the nozzle plate after the step of peeling the nozzle plate from the substrate (99).

31. 31. The method of claim 29 or claim 30, comprising removing the temporary adhesive after the step of peeling the nozzle plate from the substrate (99).

32. 32. The method of any of claims 29 to 31, wherein the step of forming the one or more frames (60) comprises an electroplating process.

33. 33. The method of any of claims 29 to 32, wherein anchors (95) are disposed at the outer peripheral edges (94) of one or more of the sub-strips (93), and the step of forming one or more frames (60) around the one or more sub-strips (93) comprises forming frame material inside and / or around the one or more anchors (95).

34. 34. The method of any of claims 29 to 33, further comprising forming an outer frame (75) before the step of forming the one or more frames (60).

35. 35. The method of claim 34, wherein the outer frame (75) is a polymer outer frame (75) formed by spin coating and photolithography.

36. 36. The method of claim 34 or claim 35, including filling gaps between the outer frame (75) and the sub-strip (93).

37. 37. The method of any of claims 29 to 36, comprising electroplating nickel.

38. 38. A method according to any one of claims 29 to 37, wherein two or more sub-strips (93) are spaced apart by a separation distance (Sd) to form a bridge (81) between said sub-strips (93).

39. 39. The method of any of claims 29 to 38, wherein the one or more sub-strips (93) comprise two or more stepped portions (97), and the step of providing the sub-strips (93) comprises arranging two or more sub-strips (93) such that two of the stepped portions (97) are located adjacent to each other on opposite sides of the sub-strips (93).

40. A method for manufacturing a nozzle plate for a droplet ejection head, comprising: forming a frame (60); forming one or more openings (61) in said frame (60), each of said openings (61) being provided with a support shelf (67a, 67b); applying adhesive to the support shelves (67a, 67b) and / or portions of the border edges (64a, 64b) of the opening (61); providing one or more sub-strips (93) in each of said openings (61) such that a portion of said sub-strips (93) is supported by said support ledge; and curing the adhesive to attach the sub-strip (93) to the frame (60).

41. 41. The method of claim 40, wherein forming the one or more openings (61) comprises etching or sandblasting.

42. 42. A method according to claim 40 or claim 41, wherein an actuator component is applied to one or more of the sub-strips (93) before the step of providing the sub-strips (93) in the openings (61).

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